Abstract: A method to confine a nuclear reactor fuel bundle assembly including: inserting a lower portion of the fuel bundle assembly into an open end of a lower fuel particle barrier; supporting the lower portion of the fuel bundle with the lower fuel particle barrier; grasping the lower portion of the fuel bundle assembly with the lower fuel particle barrier; lowering an upper fuel particle barrier over an upper tie plate of the fuel bundle assembly; moving at least a portion of a handle fixed to the upper tie plate through an open slot in the upper fuel particle barrier; closing the open slot with a closure device after the handle passes through the slot, and preventing fuel particles being released from the nuclear reactor fuel bundle assembly by the upper and lower fuel particle barriers.

Abstract: This invention relates to a nuclear plant having a reactor vessel and a fluid circuit including flow path defining means, defining a flow path for circulating a reactor coolant fluid from and to the reactor vessel. The nuclear plant includes a particle collection zone defined along at least part of the length of the flow path, and particle deflection means arranged in particle deflecting relationship with the flow path to deflect particles from a fluid stream in the flow path into or toward the particle collection zone.

Abstract: A support grid for a nuclear fuel assembly, the fuel rod assembly having a generally cylindrical fuel rod with a diameter, wherein the support grid includes a frame assembly having a plurality of outer straps and a plurality of helical frame members. The helical frame members have a contact portion structured to contact an adjacent helical frame member and at least one helical fuel rod contact portion with a lesser diameter. The lesser diameter is generally equivalent to the fuel rod diameter such that a fuel rod disposed in the helical frame member would engage the inner helical frame member at helical fuel rod contact portion. The helical frame members are coupled to each other at the contact portions thereby forming a grid. The plurality of outer straps are disposed about the perimeter of the helical frame members.

Abstract: Provided is a sliding support and a system using the sliding support unit. The sliding support unit may include a fulcrum capture configured to attach to a support flange, a fulcrum support configured to attach to the fulcrum capture, and a baseplate block configured to support the fulcrum support. The system using the sliding support unit may include a pressure vessel, a pedestal bracket, and a plurality of sliding support units.

Abstract: A device and method for stabilizing a dryer assembly in a reactor pressure vessel of a nuclear reactor including a spring assembly dimensioned and positioned within the reactor pressure vessel for applying a stabilizing force to the dryer assembly relative to the reactor pressure vessel.

Abstract: A compressed powder composite (CPC) material for absorbing neutrons emitted from spent nuclear fuel thereby preventing the initiation of a chain reaction. The CPC material is typically provided as a substantially insoluble cylindrical pellet that is highly resistant to corrosion and is not subject to the failure modes associated with the alloy materials typically used in neutron absorption materials. The pellet preferably includes a dendritic nickel powder substantially uniformly mixed with a neutron absorber powder material, preferably boron carbide. Tubes filled with CPC materials, such tubes for replacing control roads so that a spent nuclear fuel assembly may be disposed of substantially indefinitely.

Abstract: The present invention relates to nuclear fuel compositions including triuranium disilicide. The triuranium disilicide includes a uranium component which includes uranium-235. The uranium-235 is present in an amount such that it constitutes from about 0.7% to about 5% by weight based on the total weight of the uranium component of the triuranium disilicide. The nuclear fuel compositions of the present invention are particularly useful in light water reactors.

Abstract: A control rod for a pressurized-water nuclear reactor contains an absorber rod which is arranged in a casing tube. At least in a lower section, the absorber rod is provided with at least one recess which takes up at most a portion of the circumferential surface of this section. This reduces problems associated with an expansion in the volume of the absorber rod.

Abstract: A boiling water nuclear reactor (BWR) multi-stage jet pump mixer assembly according to a non-limiting embodiment of the present invention may include at least one nozzle disposed above a first throat structure which is arranged within a second throat structure. The multi-stage jet pump mixer assembly is configured such that when a drive flow is discharged from the nozzle into the first throat structure, a first suction stage occurs in that a first entrained flow is drawn into the first entrainment entrance and forms a mixed flow. The mixed flow exiting the first throat structure then induces a second entrained flow into the second entrainment entrance during a second suction stage. By employing a multi-stage approach, jet pump efficiency may be improved.

Abstract: A method for underwater packaging of radioactive materials includes creating a vacuum in a cavity of a cleaning device to automatically cause a portion of the cleaning device to move upward to actuate the cleaning device from an open position to a closed position; mounting the cleaning device inside a safe containment area of a transportation and/or storage device; placing the transportation and/or storage device in a pool after filling the safe containment area with water; loading a radioactive material into the safe containment area; closing the transportation and/or storage device using at least one cover; extracting the transportation and/or storage device from the pool; draining the water inside the safe containment area; and creating a pressure differential in the safe containment area to dry the safe containment area, wherein the pressure differential causes the cleaning device to automatically actuate from the closed position to the open position.

Abstract: A joint tong apparatus for a radiation shielding facility. A spherical ball has a through-hole. An inner spherical socket and an outer spherical socket are installed in a hole formed in a partition between a radiation-shielded room and a control room so as to enclose the spherical ball on inner and outer sides. A bar is inserted and coupled into and to the through-hole of the spherical ball. An inner joint assembly has a first housing coupled to a shielded room-side end of the bar and a first pivot member pivotably mounted on a free end of the first housing. An outer joint assembly having a second housing coupled to a control room-side end of the bar and a second pivot member pivotably mounted on a free end of the second housing. The apparatus further includes a tong assembly, a handle assembly, a tong manipulation cable, and a pair of pivot manipulation cables.

Abstract: An outer filter removal tool for a boiling water reactor control rod drive that uses a mechanical advantage obtained through the use of lead screw threads to pull the outer filter off of the control rod drive. Fingers on the tool are closed around the upper flange of the outer filter by sliding a collar over the outwardly biased fingers. A shaft extending through the tool is rotated which in turn extends a push plate against the control rod drive index tube causing the fingers to pull against the upper flange on the outer filter until the filter is freed from the control rod drive. The tool will hold the filter in place until affirmatively released for proper disposal.

Abstract: Provided is a modified target assembly in which the target fluid is moved within the target assembly in a manner that increases the effective density of the target fluid within the beam path, thereby increasing beam yield utilizing forced convection. The target may also include optional structures, such as nozzles, diverters and deflectors for guiding and/or accelerating the flow of the target fluid. The target assembly directs the target fluid along an inner sleeve in a direction opposite the direction of the beam current to produce a counter current flow and may also direct the flow of the target fluid away from the inner surface of the inner sleeve and toward a central region in the target cavity. This countercurrent flow suppresses natural convection that tends to reduce the density of the target fluid in the beam path and tends to increase the heat transfer from the target.

Abstract: A method of cleaning sludge from the tube sheet (34) of a nuclear steam generator (10) includes introducing a moveable sludge lance (76) said moveable sludge lance having duel lance heads (77) through handholes (62) in the side of the generator and into a central tube lane (60) having a central stay rod (61) and sludge lancing with high pressure fluid through the row 1 tubes (85) in the tube lane, where the distance (200) between the dual lance heads (77) is wide enough to allow the dual lance heads to extend beyond the central stay rod (61).

Abstract: A method of calibrating a nuclear instrument using a gamma thermometer may include: measuring, in the instrument, local neutron flux; generating, from the instrument, a first signal proportional to the neutron flux; measuring, in the gamma thermometer, local gamma flux; generating, from the gamma thermometer, a second signal proportional to the gamma flux; compensating the second signal; and calibrating a gain of the instrument based on the compensated second signal. Compensating the second signal may include: calculating selected yield fractions for specific groups of delayed gamma sources; calculating time constants for the specific groups; calculating a third signal that corresponds to delayed local gamma flux based on the selected yield fractions and time constants; and calculating the compensated second signal by subtracting the third signal from the second signal. The specific groups may have decay time constants greater than 5×10?1 seconds and less than 5×105 seconds.

Abstract: A protector bottom grid for a nuclear fuel assembly that includes three laterally staggered and horizontally oriented protrusions that extend into the fuel rod cell of a support grid below a vertically oriented spring. The three staggered protrusions extend into the cell a distance that maintains a space between the protrusions and the fuel rod. The vertically oriented spring biases the fuel rod against a dimple extending from the opposite cell wall that is at an elevation just above the spring. The protrusions below the spring trap incoming debris in the area of the fuel rod end cap and protect the fuel rod cladding from fretting.

Abstract: A nuclear reactor fuel bundle confinement system including: a fuel bundle with an upper tie plate; a channel enclosing the fuel bundle; a handle for the fuel bundle extending above the fuel bundle; an upper fuel particle barrier positioned over the upper tie plate and above the fuel rods, wherein the fuel particle barrier has a permeable panel at least co-extensive with an open area of the upper tie plate; a slot in the permeable panel through which passes the handle, and a closure device on the fuel particle barrier having a closed position which covers the slot and an open position that leaves the slot open; a lower fuel particle barrier positioned over the lower tie plate and below the fuel rods, wherein the lower portion of the fuel bundle assembly is grasped by the lower fuel particle barrier.

Abstract: A nuclear power plant is provided including a BWR, a reactor cooling system cooling the BWR, an HWC hydrogen injection system connected to the reactor cooling system and an alcohol injection system connected to the reactor cooling system. Methods for providing methanol and hydrogen are also provided.

Abstract: A method for collecting data regarding the operating condition of a nuclear reactor core including: positioning a first linear array of gamma thermometer (GT) sensors in a first instrument housing; positioning a second linear array of GT sensors in a second instrument housing, wherein the GT sensors are arranged asymmetrically along the linear arrays and the second linear array is asymmetrical with respect to the first linear array; positioning the first instrument housing in the reactor core at a first core location and positioning the second instrument housing at a second core location symmetrical with respect to the first core location; collecting core condition data from at least one of the GT sensors in the first linear array of GT sensors, and applying the collected core condition data as data collected from the second linear array.

Abstract: A new nuclear fuel element has been developed to be used in particular in fourth generation gaseous heat exchanger reactors working with a fast neutron flow. With a composite plate structure, the element (1) according to the invention comprises a network of cells (8), more preferably of honeycomb shape, in each of which is placed a nuclear fuel pellet (10). Radial and axial gaps are provided in each cell (8) to compensate for the differential expansion between fissile materials and structural materials inherent in the operation of the plate (1).